Here's what rhymes with porrigendum.
referendum Words that almost rhyme with porrigendum
tendon dentin intention indention momentum distention inattention hempen intervention abstention subvention supervention contravention nonintervention circumvention denim seldom venom addendum plenum bedlam jetsam phenom welcome cerebellum harem vellum velum webcam envenom spectrum rectum septum flagellum plectrum unwelcome antebellum interregnum bubblegum antiserum